Hybrid macrocycle formation and spiro annulation on cis-syn-cis-tricyclo[6.3.0.0(2,6)]undeca-3,11-dione and its congeners via ring-closing metathesis

Modular Approaches to Cyclopentanoids and their Heteroanalogs

Cyclopentanoids and their derivatives are interesting targets in synthetic organic chemistry due to their extensive applications in various branches of chemical sciences like pharmaceuticals, natural and non-natural products. In view of these applications, several synthetic strategies have been developed in the past three to four decades. In this article, we describe our work towards the synthesis of cyclopentanoids and their heteroanalogs involving diverse synthetic strategies during the past two decades. Among these, photo-thermal olefin metathesis, ring-closing metathesis, ring-rearrangement metathesis, cyclopentane annulation, [2+2+2] cycloaddition and Diels–Alder reactions have been used to assemble cyclopentane rings of diverse architecture.

1 Introduction

2 Synthesis of Spiro[4.4]nonane (A1) Derivatives

3 Synthesis of Octahydropentalene (A2) Derivatives

4 Synthesis of Linear Triquinanes (A3)

5 Synthesis Spiro Triquinanes (A4)

6 Synthesis of Angular Triquinane (A5) Systems

7 Synthesis of Hexahydro-2′H-spiro[cyclopentane-1,1′-pentalene] (A6) Ring System

8 Synthesis of Dispiro[4.1.47.25]tridecane (A7) Ring System

9 Synthesis of Hexahydro-1H-3a,7a-propanoindene Ring System

10 Synthesis of Linear Tetraquinanes (A11 and A12)

11 Synthesis of Tetrahydro-1′H,3′H-dispiro[cyclopentane-1,2′-pentalene-5′,1′′-cyclopentane] (A13) Ring System

12 Synthesis of Decahydro-1H,8H-dicyclopenta[a,h]pentalene (A14) Ring System

13 Synthesis of Dodecahydro-1H-dicyclopenta[a,d]pentalene (A15) Ring System

14 Synthesis of Octahydro-1′H-spiro[cyclopentane-1,2′-cyclopenta[c]pentalene] (A16) Ring System

15 Synthesis of Decahydrospiro[cyclopentane-1,7′-cyclopenta-[a]pentalene] (A17) Ring System

16 Synthesis of Compact Tetraquinane (A18)

17 Synthesis of Higher Polyquinanes

18 Conclusions

19 Acronyms

Design and Synthesis of Polycycles, Heterocycles, and Macrocycles via Strategic Utilization of Ring-Closing Metathesis

In this perspective, we summarize new synthetic approaches for the construction of various polycyclic compounds involving ring-closing metathesis as a key step. In this regard, we used ring-closing metathesis in combination with other popular reactions like Suzuki-Miyaura coupling, Claisen rearrangement, Fischer indolization, Grignard addition, Diels-Alder reaction, and [2+2] cycloaddition reaction etc. To this end, a variety of functional molecules such as α-amino acids, cyclophanes, heterocycles, propellanes, spirocycles, and macrocycles have been prepared. The strategies developed and the molecules prepared here play a key role in designing new materials and also act as lead compounds in drug design. The strategies and tactics developed here are useful to design polycycles, macrocycles, and heterocycles of diverse ring systems.